This Asiana Airlines Boeing 777 crash landed on the runway at San Francisco International Airport on July 6. / KPIX via AFP/Getty Images

by Ben Mutzabaugh, USA TODAY

by Ben Mutzabaugh, USA TODAY

Two runways have reopened at San Francisco International (SFO), the airport said in a tweet at 6:28 p.m. ET.

That's welcome news for thousands of passengers flying through SFO, where all flights had been grounded following the afternoon crash landing of an Asiana Airlines Boeing 777.

However, many passengers will have to scramble find new options to get to their destinations. More than 425 flights had been canceled at SFO as of 10:55 p.m ET, according flight-tracking firm FlightAware. Additionally, more than 70 SFO-bound flights had been diverted to other cities, FlightAware CEO Daniel Baker said.

Against that backdrop, San Francisco airport had already warned passengers via Twitter that it is "currently experiencing a high volume of traffic" as of 6:26 p.m. ET. The airport said customers should contact their airlines for more information.

Numerous local news reports described the scene inside SFO's terminals as chaotic as fliers plotted their next moves following the crash landing.

It was likely that all airlines serving SFO would enact flexible rebooking policies to allow passengers to change their plans to avoid the schedule disruptions there.

SFO's two busiest carriers -- United and Virgin America -- each announced that they would allow customers ticketed to fly to, from or through San Francisco through Monday to change their flights at no cost.

Most other SFO had done the same by Saturday evening.

Still, customers whose flights are canceled now must find new options to get to their destinations. With planes flying at near-record capacity, that would be a challenge even during normal conditions.

The same goes for customers who ended up in unexpected cities after their flights diverted away from San Francisco.